Manufacture of wall board



M y 1932- e. M. THOMSON 1,859,353

MANUFACTURE OF WALL BOARD Filed March 10, 1950 INVENTOQ: GECIRGE. M. THOMSON- bub/14%,

BY ATTORNEY6.

Patented May 24, 1932 UNITED STATES PATENT OFFICE GEORGE MILLER THOMSON, OF CALEDONIA, ONTARIO, CANADA, ASSIGNOB TO GYPSUM, LIME AND ALABASTINE, CANADA, LIMITED, OF PARIS, ONTARIO, CANADA MANUFACTURE OF WALL BOARD Application filed March 10, 1930. Serial No. 434,787.

This invention relates to the manufacture of wall board of the type consistlng of a paper-covered layer or core of hardened, initiall plastic material. In the manufacture 0 such wall board it is customary to squeeze the plastic material, such as slurry of gypsum, between paper liners, an adhesive being mixed with the slurry or applied to the paper liners to ensure that the core will be well bonded to the paper when the core hardens.

The present invention has for its object to rovide an improved method of and means or applying adhesive whereby the thickness and width of the film of adhesive applied to the paper can be controlled with precision.

The invention consists in the steps and arrangements and combination ofparts hereinafter described and more particularly pointed out in the appended claims.

Referring now to the accompanying drawings, which illustrate diagrammatically and by way of example one form of apparatus for carrying the invention into effect,

Figure 1 is a side elevation of the 1mproved apparatus;

Figure 2 is an enlarged side elevation of the paste-applying roller and associated parts for the upper paper liner, and

Figure 3 is a plan view substantially on the line 33 of Figure 1. v

The numerals 1 and 2 respectively indicate the top and bottom paper liners, which are simultaneously and continuously advanced in the direction of the arrows. The top liner 1 passes forwardly from a supply roll 3, over a guide roll 4, from which it travels in a rearwardly and downwardly inclined direction over a supporting roll 5, and then downwardly and around a squeeze roll 6.

The bottom liner 2 proceeds in a forwardly and upwardly inclined direction form a supply roll 7, over a supporting roll 8, and thence forwardly over a squeeze roll 9, which cooperates with the upper squeeze roll 6.

A supply of plastic material 10 to form the core of the board is fed on to the bottom liner 2 from a chute 11, this material being sure through pipes 15 to nozzles 16 and 17,

which are arranged to direct adhesive into the bight between the pairs of rolls 5, 12 and 8, 13. The upper nozzle preferably discharges on to the roll 12 at a point slightly in rear of the plane in which it is nearest to the liner 1. (See Figure 3.) The lower nozzle 17 preferably discharges on to the liner 2 at a point slightly in rear of the plane at which'the roll 13 is nearest to the liner.

The r0lls112 and 13 do not press on the liners 1 and 2, but are so arranged in relation to the liners as to control the thickness of the film of adhesive which is applied to the liners. The rolls 12 and 13 are preferably mounted in such manner that the thickness of the adhesive film can be readily adjusted. For example, the spindles 18 of the rolls '12 and 13 may be ournalled in bearing blocks 19, slidably mounted in recesses 20 in any suitable frame members 21, manually operable screws 22 being provided to move the rolls towards or away from the respective liners as desired. By rotating the screws 22 the distance between the rolls 12 and 13 and their respective paper liners 1 and 2 can be adjusted with great recision to produce the desired thickness 0% adhesive film, indicated at 23. Means are provided for varying the rate of feed from the nozzles 16 and 17 so that the Width of the film 23 can be adjusted as desired. From Figure 3 is will be seen that, after striking the roll 12 the adhesive spreads laterally into a film which attains its maximum width at the plane in which the roll 12 most closely a proaches the liner 1. This maximum widt ma be varied in relation to the greater width 0 the paper liner by suitably controlling the rate of feed of the adhesive in relation to the speed of travel of the paper. This adjustment of the feed may be accomplished by providing the pump 14 with a variable speed drive, an electric motor 24 being indicated for this purpose together with a rheostat 25 for controlling the motor speed.

By controlling the width of the adhesive film in the manner described, the film is prevented from spreading laterally beyond the zone to which it is desired to apply the adhesive. By selecting an adhesive of a suitable viscosity, the film 23 is able to resist being squeezed further to the side by the pressure exerted by the bank of slurry 10. Any suitable adhesive, such as flour paste, starch, gum or the like, may be employed, one convenient adhesive consisting of one pound of paste flour mixed with one gallon of Water.

The foregoing description and accompanying drawings are given by way of example, and various modifications may be made within the scope of the appended claims without de arting from the invention.

t will be apparent that if an excess of paste is placed upon the paper webs, the pressure of the slurry will force such paste outwardly towards the edges of the paper webs, thus providing too much paste at the edge portions of the board. The present invention overcomes this and other difliculties and makes it possible to readily apply the paste so as to provide a uniform coating or film of the desired width on the paper webs, whereby the uniformity of the core of the board as well as that of the bond between'the 'core and liners is maintained.

I claim:

1. In the manufacture of wall board of the kind described, a method of applying adhesive to a paper web which comprises advancing said web between a support and a distributing roll arranged parallel to said support, feeding liquid adhesive into the bight between said roll and paper web, and controlling the width of the adhesive film applied to the web by regulating the rate of feed of the adhesive.

2. In the manufacture of wall board of the kind described, a method of applying adhesive to a paper web which comprises advancing said web between a support and a distributing roll arranged parallel to said support, feeding liquid adhesive into the night between said roll and paper web, and controlling the thickness of the adhesive film applied to the web by adjusting the position of said roll in relation to the paper.

3. In the manufacture of Wall board of the kind described, the method which comprises advancing a pair of paper webs between supporting rolls and distributing rolls without eing pressed upon by the distributing rolls, feeding liquid adhesive into the bights between the distributing rolls and the paper webs, controlling the width to which the adhesive films are applied to the webs by 1,859,853 I I I spreads laterally to a width depending on the rate of feed of the adhesive in relation to the speed of advance of the web.

5. Apparatus for manufacturing wall board of the kind described, comprising a support for a paper web, an adhesive distributing roll parallel to said support, means for feeding liquid adhesive into the bight between said roll and support and means for regulating the rate of feed of the adhesive.

6. Apparatus for manufacturing wall board of the kind described, comprising a support for a paper web, an adhesive distributing roll parallel to said support, means for feeding liquid adhesive into the bight between said roll and support, and means for adjusting the position of said roll in relation to the support.

7. Apparatus for manufacturing wall board of the kind described, comprising two supporting rolls, an adhesive distributing roll adjacent and parallel to each of said supporting rolls, nozzles directed into the bights between the distributing rolls and the respective supporting rolls at a point substantially midway between the ends of said rolls, pumpand pipe connections for supplying liquid adhesive to said nozzles, a variable speed drive for said pump, and means for adjusting the position of said distributing rolls in relation to said supporting rolls.

In testimony whereof I have afiixed my signature.

GEORGE MILLER THOMSON.

regulating the rate of feed of the adhesive,

controlling the thickness of the adhesive film by adjusting the position of the distributing 

